• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.136-142
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• 2001

Recently, a much amount of attention has been paid not only to produce products with precise dimensional accuracy, but also to predict and control the microstructural evolution and mechanical properties of parts. Especially, to do the latter through computer simulation, the history of states factors influencing on these evolution such as temperature, strain, strain rate etc., should be calculated and a appropriate mathematical models for the prediction of microstructural evolution must be developed. Thus, in this study thermo-viscoplastic finite element program including the model for predicting microstructural has been developed. Also for the verification of developed program warm forging process for the rotor pole was simulated and the comparison between the results calculated and ones in the literature was made.

• 경영과학
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• 제29권3호
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• pp.169-182
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• 2012

This study examines the co-evolutionary process between open innovation and firms' absorptive capacity. The effects of open innovation can be maximized through the capacity to absorb the knowledge from the external sources such as universities, government-support research institute, and private R&D centers. This study used data of STEPI technology innovation survey conducted at 2002, 2005, and 2008 (3 points measures). The data were analyzed through a structural equation model. Results suggest that open innovation at t0 point influences positively the absorptive capacity at t1 point, which subsequently enhances the intention of open innovation at t2 point. This result suggests the existence of co-evolutionary process between open innovation and firms' absorptive capacity. When knowledge comes from universities, the co-evolution has sustained; whereas when knowledge comes from private firms' R&D centers, the co-evolution has not effected. Theoretical and practical implications are discussed.

• Structural Engineering and Mechanics
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• 제24권1호
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• pp.19-29
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• 2006

The evolution process of an initially homogeneous bone structure under axial and transverse loads is investigated in this paper. The external loads include axial and external lateral pressure, electric, magnetic and thermal loads. The theoretical predictions of evolution processes are made based on the adaptive elasticity formulation and coupled thermo-magneto-electro-elastic theory. The adaptive elastic body, which is a model for living bone diaphysis, is assumed to be homogeneous in its anisotropic properties and its density. The principal result of this paper is determination of the evolution process of the initially homogeneous body to a transversely inhomogeneous body under the influence of the inhomogeneous stress state.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.146-156
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• 2020

Two High Tensile Strength Steel (EH47) plates with thickness of 70 mm were butt-welded together by multi-pass Submerged Arc Welding (SAW), also the hardness and welding residual stress were investigated experimentally. Based on Thermal-Elastic-Plastic Finite Element (TEP FE) computation, the thermal cycles during entire welding process were obtained, and the HAZ hardness of multi-pass butt welded joint was computed by the hardenability algorithm with considering microstructure evolution. Good agreement of HAZ hardness between the measurement and computational result is observed. The evolution of each phase was drawn to clarify the influence mechanism of thermal cycle on HAZ hardness. Welding residual stress was predicted with considering mechanical response, which was dominantly determined by last cap welds through analyzing its formation process.

• 디자인학연구
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• 제14권4호
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• pp.137-146
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• 2001

본 연구의 목적은 진화이론을 이용하여 제품의 진화 유형을 밝히고 이를 통해 제품의 발전과정을 이해하는데 있다. 연구의 목적을 위해 진화 메커니즘을 설정하여 제품들을 이에 적용하였고, 그 결과는 '기능의 진화', '형태의 진화', '상징의 진화' 등 세 가지 진화 유형으로 나타났다. 연구 문제인 <제품은 진화하는가>, <왜 진화하는가>, <어떻게 진화하는가>에 대한 답을 찾기 위해, 본 연구는 세 단계로 진행되었다: 첫째, 선학들의 연구 결과를 통하여 제품 진화론을 정의하였다: 둘째, 이를 바탕으로 진화 메커니즘을 설정하였다: 셋째, 제품을 진화 메커니즘에 적용하여 제품의 진화 유형을 구분하였다. 연구의 결과는 정리하면 다음과 같다. ${\bullet}$본 연구에서 제시한 진화 메커니즘은 '진화의 원인'인 '필요와 즐거움', '진화의 시점'인 '결함', '진화의 원동력'인 '이익'등으로 구성된 유기적 장치이다. ${\bullet}$제품을 진화 메커니즘에 적용한 결과, 진화 유형은 '기능의 진화', '형태의 진화', '상징의 진화'등으로 나타났다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문
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• pp.62-72
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• 1996

A process model is formulated considering the effect of crystallographic testure developed in forming process. The deformation induced plastic anisotropy can be predicted by capturing the evolution of texture during large deformatin in the poly crystaline aggregate. The anisotropic stiffness matrix for the aggregate is derived and implemented in Dulerian finite element code. As an application , the evolution of texture in rolling, drawing and extrusion processes are simulated . The numerical results show good agreement with reported experimental textures.

• 한국표면공학회지
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• 제35권5호
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• pp.325-329
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• 2002

We investigated the oxide thickness and color evolution with the oxidation temperatures between $370^{\circ}C$ and $950^{\circ}C$ for 30 minutes in an electric furnace. Oxide thickness and color index were determined by cross sectional field emission scanning electron microscopy (FESEM) images and digital camera images, respectively. We confirmed that thermal oxidation was suitable for the mass production of color-titanium products, while coloring process window was narrow compared with anodizing oxidation process.

• 소성∙가공
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• 제5권4호
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• pp.297-304
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• 1996

A process model is formulated considering the effect of crystallographic texture developed in forming process. The deformation induced plastic anisotropy can be predicted by capturing the evolution of texture during large deformation in the polycrystalline aggregate. The anisotropic stiffness matrix for the aggregate is derived and implemented in Eulerian finite element code using a Consistent Penalty method. As an application the evolution of texture in rolling drawing and extrusion processes are simulated. The numerical results show good agreements with report-ed experimental textures.

• 한국정밀공학회지
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• 제21권5호
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• pp.188-202
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• 2004

This research was designed to investigate biomechanical aspects of the evolution based on the hypothesis of dynamic cooperative interactions between the locomotion pattern and the body shape in the evolution of human bipedal walking The musculoskeletal model used in the computer simulation consisted of 12 rigid segments and 26 muscles. The nervous system was represented by 18 rhythmic pattern generators. The genetic algorithm was employed based on the natural selection theory to represent the evolutionary mechanism. Evolutionary strategy was assumed to minimize the cost function that is weighted sum of the energy consumption, the muscular fatigue and the load on the skeletal system. The simulation results showed that repeated manipulations of the genetic algorithm resulted in the change of body shape and locomotion pattern from those of chimpanzee to those of human. It was suggested that improving locomotive efficiency and the load on the musculoskeletal system are feasible factors driving the evolution of the human body shape and the bipedal locomotion pattern. The hypothetical evolution method employed in this study can be a new powerful tool for investigation of the evolution process.

• 소프트웨어공학소사이어티 논문지
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• 제26권1호
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• pp.17-29
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• 2013

소프트웨어 시스템 진화는 소프트웨어 시스템의 유지보수의 일종으로 계획적이고 체계적인 유지보수 프로세스이다. 소프트웨어 진화 연구는 기존 시스템의 비용편익 분석을 통해 시스템의 유지가치에 대한 판단 근거를 제공하며, 아키텍처를 기반으로 하는 진화는 반복적인 진화 작업의 자동화를 가능케 하여 유지보수 비용 감소를 가능하게 해주는 연구이다. 본 논문에서는 아키텍처 변환패턴을 이용한 소프트웨어 시스템 진화 프레임워크를 제안한다.